Choking device for gasoline engines



April 1934- w. VAN B. ROBERTS CHOKING DEVICE FOR GASOLINE ENGINES Filed June 20, 1930 FIG. 1

INVENTOR Va/fella? 5. Aober/fs BY j M44. TORNEY Patented Apr. 17, 1934 CHOKING DEVIC ENG E FOR GASOLINE INES Walter van B. Roberts, Princeton, N. J assignor of one-fourth to Ira J. Adams Application June 20, 1930, Serial No. 462,453

2 Claims.

This invention relates to starters for gasoline engines, for example, such as are used on automobiles and similar devices.

The present type of starting arrangement consists of a small battery operated motor that cranks the engine at relatively low speed compared to normal speeds of the engine and to produce proper suction on the carburetor jet valve it has been the practice to provide a choke valve in the air intake. This choke constricts the air pa sage to such an extent that a proper reduced pressure is obtained which draws a large amount of gasoline from the carburetor jet to start the motor.

As soon as the engine starts with these arrangements the engine shaft is rotated at a much higher speed by the explosions in the engine cylinders and this increased speed reduces the pressure in the intake to such an extent as to draw in such a flow of gasoline as to choke the motor. If the choking valve is not at once turned back towards normal the engine will stall because the mixture is too rich. Therefore, in the usual starting operation in cold weather the starter -'-1 pedal is depressed from one to half a dozen times or more with the repeated stalling of the engine until an approximately correct mixture is obtained to let the engine proceed under the normal action of the carburetor. I have devised arrangements whereby these defects may be easily avoided.

Referring to the drawing, Fig. 1 is a more or less diagrammatic illustration of the invention employing two choke valves for producing easy starting of the motor.

Fig. 2 is a modification in which only one valve is used to accomplish the results essential parts only being shown.

Referring to the drawing, the air intake 1 leading to the carburetor 2 has a choke valve 3 and an auxiliary regulator valve 4 which may be termed a partial choke. -This partial choke is connected by means such as a flexible cable 5 with the control handle 6. This control handle -has an indicator point '7 that passes over a scale 8 preferably marked with temperatures indicating the position of the handle 6 to produce the right amount of auxiliary choking to permit the engine to run on its own speed at the estimated temperature of the surrounding air.

The choke 3 is normally maintained in the open position, that is parallel with the intake pipe 1, by spring 9. The valve is also connected to an armature 10 which through influence of electromagnet 11 rotates the valve against the tension of the spring 9 to choking position when the switch 12, preferably located on the dash is closed by the operator.

The usual starting motor 13 is controlled by starting switch 14 and is connected to the flywheel of the engine or to any other appropriate rotating part in a well known way and need not be described.

The method of starting the engine with my improvement is as follows:

With switch 12 closed, when the operator energizes the starter motor 13 by closing switch S, the voltage of the battery 12' impressed across the motor terminals energizes magnet 11, causing the armat re 10 to be moved against the tension of spring 9, thus substantially placing the valve 3 directly across the channel in pipe 1. This constricts the air passage leading to the carburetor to such an extent that the slow speed oi the engine produced by the starting motor would produce suilicient vacuum, that is, reduced pressure, to produce a copious supply of gasoline for the initial starting. As soon as the engine gets under headway the operator releases the starter switch 14 thus deenergizing magnet 11, whereupon spring 9 opens valve 3. Instead of this leaving the pipe 1 entirely unconstricted, however, the operator is assumed to have previously set the auxiliary control handle 6 to the approximate temperature of the air around the automobile, for example, say 15 Fahrenheit, as marked on the dial. This setting of the handle 6 would set the valve 4 or other control arrangement to partially constrict the pipe 1 which would produce the proper amount of vacuum in the pipe to draw in a correct amount of gasoline to keep the engine running smoothly on its own power at a moderate speed. The engine would run for a considerable period with this position of valve 4 even though the mixture becomes too rich through warming of the engine parts. Preferably, however, as the engine warms up the operator returns handle 6 back to the position at which valve 4 is wide open so that the engine can run on the carburetor adjustments alone. By this double arrangement of valves the engine will be initially started and proceed on its own power without the usual repeated stalling.

In Fig.2 I have shown a modification whereby one choke valve 1 is controlled to accomplish the results of the arrangement in Fig. 1. In this modification the adjusting means 5 can be rotated in response to handle 6 of Fig. l to move the stop arm 15 to varying positions to limit the re turn of the main choke valve 3 by engaging the arm 16 on the choke valve axle 17. The arm 18 in this figure is the same as the one in Fig. 1 and further description is unnecessary except to state that the magnet 11 can close the valve 3 to full choke position but the return opening of the valve under influence of spring 9 (shown in Fig. 1) is controlled by the arm 15 previously adjusted by the operator through knob 6 on the dash. This modification thus accomplishes the same result as the double valve arrangement of Fig. 1. Control handle 6 is used alone for starting in warm Weather or when the engine is warm. In such cases the switch 12 is left open.

It of course is not essential to judge the temperature accurately in the neighborhood of the automobile in order to set the control 6, as only rough approximation of, the temperature is required for control of the motor. After a little experience practically anyone can estimate the surrounding temperature with sufiicient accuracy to operate this control mechanism.

The hand control device 6 may operate upon the carburetor needle valve to give increased gasoline supply instead of upon a choke valve and the principle of operation will be the same.

The principle of my invention may be embodied in various other ways than those shown and the invention is not to be limited to any particular arrangement.

Having described my invention, what I claim is:

1. In internal combustion engines, a carburetor air intake, an electric starting motor, choking means for said intake, a spring tending to move said choking means to open position, an electromagnet, means to simultaneously energize said motor and magnet, an armature for the magnet connected to said choking means and adapted to move it to full choke position against the tension of said spring on energization of the magnet, means to limit the amount of opening of said choking means after said magnet has been deenergized and a manual dash control for adjusting the last mentioned means to any desired amount of opening.

2. In internal combustion engines, a carburetor air-intake, an electric starting motor, a choke valve in said intake, an adjustable stop for variably limiting the opening of said valve, a spring yieldingly holding said valve open to the extent permitted by said stop, a manual dash control for adjusting said stop to the desired valve opening, an electromagnet, means to simultaneously energize said motor and magnet, an armature for the magnet connected to said valve and adapted to close it against the tension of said spring on energization of the magnet.

WALTER VAN B. ROBERTS. 

